1. Field of the Invention
This invention generally relates to a method and apparatus for establishing the rotational alignment of the resected distal surfaces of a human femur with respect to the proximal tibia to permit proper rotational orientation and the anterior and posterior location of drill holes in the distal femur for attaching a cutting block for resecting the distal human femur.
2. Description of the Prior Art
Different methods and instruments have been developed to enable a surgeon to resect a human distal femur to attach a distal femoral prosthesis to the distal femur. Keeping in mind the ultimate goal of the procedure is to restore the knee joint to normal function, it is critical that the implant's location and orientation be consistent with the state of the ligaments, tendons and other soft tissue remaining in the knee joint after completion of the surgery.
It is common to use the central axis of the femur, the posterior and distal femoral condyles, and/or the anterior distal femoral cortex as guides to determine the location and orientation of the distal femoral resections. The location and orientation of these resections are critical in that they dictate the final location and orientation of the distal femoral implant. It is commonly thought that the location and orientation of the distal femoral implant are the most critical factors in the success or failure of the artificial joint.
Past efforts have not been successful in consistently and properly locating and orienting distal femur resections. Such efforts are set forth in the following patents, none of which teach or suggest all of the benefits and advantages of the patents.
Androphy, U.S. Pat. No. 4,487,203, discloses a knee resection system comprising a guide member, femur and tibia guide rods, a tibia adaptor, a tibia bar, and a femur bar for establishing equal flexion and extension gaps. The guide member block receives a femur guide rod inserted into a femur. A guide rod extends in a vertical direction from the guide member block. When aligned with the femur, pins are pushed through the guide member block, to fix the guide member block with respect to the distal femur. Then, the distal femoral condyles are resected with an oscillating saw through guide slots in the guide member block. A guide member block is then attached to a tibia guide rod extending into the tibia, the tibia guide rod having a second guide at a right angle thereto for receiving the guide member block. The guide member block is then positioned by means of a tibia bar and, when properly aligned, is fixed to the anterior side of the proximal tibia with pins. The tibia is then resected with an oscillating saw inserted through slots in the guide member block. Next the flexion gap between the resected proximal tibia and the resected posterior distal femur is determined by turning the guide rod inserted into the femur to orient the perpendicular section towards the tibia to identify the distance between the tibia and the femur with the collateral ligaments extended taughtly. Then, the knee is placed in extension, the guide member block is placed onto the guide rod, and the guide member block is positioned along an extension of the femur block. When properly aligned, guide member pins are pressed to secure the guide member to the distal femur. The knee is then placed in flexion and the distal femur is resected with an oscillating saw inserted through slots in the guide member block.
Rohr, Jr., U.S. Pat. No. 4,566,448 discloses a ligament tensor device having a first member to engage the tibia and a second member to engage the intercondylar notch of a femur and a means for moving the second means with respect to the first means for applying a selected tension to the ligaments of the joint. Additionally, the invention includes cutting guide slots for guiding the cutting of the femoral condyles. A pressure plate is placed on the sectioned surface of the tibia. The pressure plate is interconnected with a cutting guide head which is contacted by a threaded screw extending from the support housing structure. The support housing structure is movable with respect to the tibia cutting guide head by means of the screw member. The support housing structure is attachable to the tibia to move to the femur away from the tibia to tension the ligaments of the knee structure. The femur may be resected through cutting slots on the support housing structure.
Kenna, U.S. Pat. No. 4,653,488 and U.S. Pat. No. 4,787,383 discloses holes drilled into the distal femur and a femoral cutting jig attached thereto. The femoral cutting jig is attached with lock-in pins to the femur. An axial alignment guide is used to establish the proper varus-valgus and flexion extension alignment of the distal femoral cuts. A guide pin extends from the long axial alignment guide and the pin is properly positioned when it is parallel to the femoral shaft. The distal femoral cutting jig is positioned accordingly and locked into place with a jig having teeth for engagement with the femur. Rotation, medial-lateral and anterior-posterior orientation of the femoral prosthesis is determined by a femoral drill jig having two posterior skids (or tongs) which are slid between the posterior femoral condyles and the tibial plateaus. The jig contains two holes for use in making the holes for the femoral prosthesis fixation studs. A cutting jig may then be attached for making anterior and posterior femoral cuts. To achieve correct tibial axial alignment, longitudinal traction is applied to the foot to bring the tibial shaft parallel to an alignment pin. Then the transverse tibial cut may be made.
Russell, et al, U.S. Pat. No. 4,722,330 discloses distal femoral surface guide for mounting on an intramedullary alignment guide for use in shaping the distal femoral surface. A conventional shaping means such as an oscillating saw or hand saw is introduced into the guide surface to resect the femur. The device also includes stabilizing members with threaded knurled cap bolts with points that extend along the sides of the femur to stabilize the device.
Fargie, et al, U.S. Pat. No. 4,736,737 is a tibial cutting jig, having a base that interconnects with a intramedullary alignment rod installed along the axis of the tibia. The base includes outriggers carrying measurement keys for spacing the base a preselected distance above the tibia. A saw guide is attached to the base and is positioned to allow for cutting of the tibia at a selected position.
Whiteside, et al, U.S. Pat. No. 5,002,545 discloses a shaping guide for accurately shaping the tibial plateau comprising an alignment rod located anterior to the anterior cruciate ligament and along the anterior cortex of the intermedullary canal of the tibia. The shaping guide is interconnected with the rod and is adjustable with respect to the rod to control the amount of resection of the tibial plateau by raising or lowering the cutting guide surfaces. The device includes a pin which is inserted into a hole on the alignment guide for setting rotation alignment by aligning the pin with the intercondylar notch of the femur.
Poggie et al., U.S. Pat. No. 5,250,050 discloses an apparatus for use in a total knee prothesis comprising cutting guides, templates, alignment guides, a distractor and clamping instruments. The lateral anterior prominence is resected from the distal femur for preparing the distal femur for the distal femoral cutting block. A hole is first drilled in line with the medullary canal midway between the medial and lateral femoral condyles just anterior to the posterior cruciate. The right or left alignment fork is introduced into the medullary canal. The femoral distractor is slid onto the alignment fork and the leg extended. The distractor is keyed to the femur at the appropriate angle of valgus from the mechanical axis of the frontal plane and perpendicular to the sagittal plane. The femoral distractor sits flush on the cut proximal tibia. A lateral and medial arms of the distractor are distracted up to the femoral condyles with the knee in full extension. Ligamentous releases may be performed to balance the ligaments. The drill guide slides up to the anterior femur and two pins may be tapped through the holes to correspond to the tibial thickness. The drill guide slides off leaving the pins in place. The tension of the distractor may be released and the distractor removed. The knee is flexed to 90 degrees and the alignment fork is removed. The distal cutting guide slides onto the pins and an oscillating saw is used to resect the distal femoral condyles. The distractor is then inserted between the femur and tibia, and it is distracted. The drill guide is used to tap two pins into the resected femur. Then the drill guide is removed, tension released and the distractor removed. Then the AP sizer is slid onto the pins and the feelers engaged and the body is lowered and rotated until the feeler touches the high point of the anterior cortex. Then a chamfer block is engaged with the pins and femoral cuts may be made.
Stillwell, U.S. Pat. No. 4,457,307, which discloses a movable saw and saw carriage which may be mounted to a patient's femur and positioned to cut the femur bone. An elongated rail is secured substantially parallel to the femur. A saw carriage and a carriage housing are attached to the rail. The saw has a blade extending substantially parallel to the direction of linear movement of the saw carriage. The saw carriage is slidably guided along paths substantially parallel to the elongated rails for making cuts in the femur bone. The saw may be positioned in a plurality of second positions where the saw carriage is slidably guided in paths substantially perpendicular to the elongated rail for making traverse distal femur cuts and for scoring the tibia cortex. Additionally, the saw may be positioned in a plurality of third positions where the saw carriage is slidably guided to form an acute angle with the elongated rail for making anterior and posterior femur chamfer cuts.
Keller, U.S. Pat. No. 4,586,496, discloses a surgical chisel having a flexurally rigid chisel shank and a thin, elongated chisel blade fixed at its front end. A chisel guide is provided having slides for displaceably guiding the blade and shank in a longitudinal direction.
Zarnowski et al., U.S. Pat. No. 4,892,093, discloses a cutting guide for a saw blade for resecting a femur. The device is attached to a femur after the distal end has been removed and a transverse surface has been established. The cutting guide includes a base member having a planar base surface. A pair of laterally spaced-apart locating and securing posts are integral with the base member and project in a direction normal to the base surface to interconnect with the femur. Guide members in the form of cylindrical bars are positioned within side members attached to the base. A saw blade may be inserted between the guide surfaces to properly position the blade to cut the femur.
Vandewalls, U.S. Pat. No. 4,896,663, discloses a drill for drilling a hole into a femur. The device includes a positioning mechanism to firmly engage the outer peripheral surface of the femoral head and the femoral neck. This immobilizes the drill bushing relative to the femur and orients the axis of the drill with the central axis of the femur.
Schmidt, U.S. Pat. No. 5,049,149, discloses a sawing gauge system for intertrochantery accommodation osteotomies for removing a wedge-shaped section of bone with a predetermined wedge-angle so that an optimal pre-stress load F can act.
Lackey, U.S. Pat. No. 5,053,037, discloses a femoral drill guide with interchangeable femoral collets, a femoral reamer and a femoral anterior/posterior cutting block with an adoptable anterior femoral ledge. A plurality of diagonal slots are provided for making diagonal cuts in the distal end of the femur.
Ferrante et al. U.S. Pat. No. 5,098,436, discloses a modular guide for shaping a femur comprising a first bracket defining a generally U-shaped structure having an internal surface adapted to be seated on the distal aspect of a resected femur bone and an elongated central opening appointed to expose a selected area of the resected femur, including a curved track for guiding a first shaping tool along a predetermined path for controlled shaping of a curved patellar groove and a portion of the selected area exposed through the opening. A second bracket defines a linear slotted bore extending generally parallel to the long axis of the femur for guiding a second shaping tool to form a relatively deep recess accommodating an intercondylar-stabilizing housing of a knee implant.
Brown, U.S. Pat. No. 5,234,432, discloses a method of cutting the proximal end of a femur prior to cementing in a prosthesis for reconstructive hip surgery.
Additionally, Whiteside, U.S. Pat. No. 4,474,177 describes instruments for creating the distal femoral surfaces where a guide is used to index a flat surface used to guide the distal femoral resection. Kaufman, et al. U.S. Pat. No. 4,721,104 describes a method of preparing the intracondylar area of the distal femur. In addition, Kenna, U.S. Pat. No. 4,787,383 describes a saw and saw guide used to perform the most distal planar femoral resection. Jellicoe, U.S. Pat. No. 5,047,032 utilizes a side cutting drill to form the distal femoral surface.
These previous devices have not dealt with properly locating and orienting placement of a cutting guide on the distal femur, for resecting the femur, based on the orientation of the resected proximal tibia. These past efforts locate and orient cutting guides on the distal femur by "eye" or other, equally imprecise methods. Accordingly, none of these prior efforts, taken alone or in combination, teach or suggest the benefits of the present invention, nor the structure and method of the present invention for achieving these benefits.